No or only slight movement on front loader

[RWolf]

This is my first post and I'm sure this has been addressed before but I can not find the thread.

Here's the setup; Power King (circa 1973) with hydraulic front loader and hydraulic 3pt. Originally I took it into a hydraulic shop to have them check the system as the front loader was having problems lifting its own weight. What they told me was the pump was bad. The said it was only putting out about 500psi (I know from other threads pumps move fluid, restrictions make pressure). Anyway they wanted big bucks to get a pump and I already had found a source for Haldex pumps at a fraction of the price they wanted. I had asked them what size pump to get and they told me a 1-2 gpm pump was all that was needed. From the parts manual I had found this to be true only if the hydraulic 3pt was installed. When a front loader was installed that moved up to a 7gpm pump. They convinced me that a 1-2 was all that was needed. Anyway after installing new pump (by them) everything worked but you could activate the loader hydraulics and go get a cup of coffee before it raised the bucket to full height. So I got a 4-8 gpm pump and installed it myself as I didn't trust this shop. Because the new pump had larger hose requirements I changed the hose from the resivovir (sp) to pump (draw) and from pump to the loader valve (2 spool). Everything worked great for the first 1-2 lifts and then basically died. There is another valve in line with the loader valve that controls the 3pt. It works ok albite a little slow but not bad. The only thing I have done with the loader valve is to check the bypass (I believe) and had initially reinstalled it wrong but re-installed it ok. I have attached a basic drawing of the system.

 

[MrJimi]

Welcome to TBN and It sounds like your low on fluid and I could be wrong but check the level and top it off if needed
We have lot's of hydraulic experts here that will chime in with your answer

 

[RWolf]

Thank you, I have been searching the various threads for about 2 weeks trying to find my answer. Fluid level was one of my first thoughts and I have topped the tank off. I have also place a pressure gauge inline between the pump and the valve. It reads 0 psi. when all controls are in their neutral position. Activating the loader does not change the pressure. When I active the 3pt and allow the cylinder to go to its end of travel pressure will climb to about 1000psi. I've also bled the lines going to the bottom of the loader lift cylinders (trying to keep things one at a time). Because of me messing with the bypass valve I was wondering if I goofed it up and the system was bypassing the loader controls completely. Although I am fairly profecient with mechanical devices hydraulics are new to me and I'm trying to repair this as safe as I can be.

 

[RWolf]

Thank you so far everyone. I've gotten som PM's etc. One thing was noted was my drawing didn't get uploaded correctly so I redid it and uploaded it again. I hope this helps.

 

[MrJimi]

File is acting same way here = not found

 

[kennyd]

First, Welcome to TBN RWOLF!

Now, To check the relief valve setting, you need to plumb the gauge into one of the loader ports, another words disconnect a line going to one of the FEL cylinders, or plug it into a QD coupler if you have them-now operate the spool to send fluid to that port and read the gauge as the pump must be dead-headed to get an accurate relief valve pressure reading. Having the gauge plumbed in-line will not do you any good to set the relief valve.

I think this is where you need to start troubleshooting at this point. Also can you answer these questions:

Does the FEL valve get warm or hot when the tractor is running?
Is the fluid milky like during/after running?
Are there signs of excessive air bubble in the tank during/after running?
When you operate the 3PH cylinder to it's stop does the engine bog down?

Oh, and your file worked fine for me...

 

[RWolf]

Again many thanks I'm getting several great responses.

Weather permitting I'll re-plumb my guage tonight (storms coming supposedly).
Valve doesn't get warm but again I haven't ran it for any length of time so I don't damage anything.
Fluid looks good. I cracked the line to the lift cylinder and only saw a few bubbles and then they stopped.
Last time I looked in the tank there was some bubbling at first but I attribute that to the fact I had the system open.
Yes operating the 3pt when the cylinder reaches the end of travel the engine bogs down some and I build about 1000psi on the guage (inline).

 

[kennyd]

I am leaning towards a bad or mis-adjusted relief valve...

 

[Leejohn]

You might have a coupler not plugged in all the way or maybe a crossed line 1000psi I would think would lift the loader, but slow.

 

[RWolf]

Well I got to work on the tractor today. Checked/blew out all lines, checked bypass valve and all seems ok. I also added a spacer (washer) behind the bypass valve spring. Nothing changed except that when I run the 3pt ram to it's end the engine will bog down a bit more. I'm perplexed. I wouldn't think a control valve would go out so quick.

I'm not sure if I mentioned this before but the control valves are dukes (victor?).

Again thanks for the help so far.

Richard